Thyristor-based random access memory (TRAM) is a promising solution for embedded applications due to low power (about 1 pA/cell) and high-density capabilities. Current TRAM systems are configured in arrays, such as cross-point arrays comprising thyristors without diodes. In a cross-point array, voltage (IR) drops on the word-line (WL) for wide-input/output (TO) may impact read speed and write efficiency. In current TRAM architectures, a write voltage may crash, i.e., may not have sufficient write voltage. Writing multiple bits in parallel causes some of the bits to be written to a high current state earlier than other bits. In current designs, the early-write cells are not current limited and may draw too much current on the word-line, causing a voltage drop (delta V=IR) on the word-line. As a result, the write operation of the remaining cells will be impacted due to the drop in write voltage on the word-line. A TRAM element is typically biased at a high current during a write operation and current spikes can occur.
TRAM elements During a write operation, the resistance of a thyristor is changed between a high resistance phase (generally corresponding to a logic “0”) and a low resistance phase (generally corresponding to a logic “1”) in response to electrical current signals supplied via the word-line and the bit-line. Transitions between a high-resistance phase and a low resistance phase occur when suitable current bias signals are applied to the word-line and/or the bit-line to forward bias a thyristor. The biasing current of the word-line is applied through each cell simultaneously during a write operation. Writing multiple bits on a single word line row causes the current in each of the cells of a row to increase. After the write operation, a voltage crash occurs due to the high current developed on the word-line 18 due to multiple cell writes. As current increases, the voltage on the line also increases and then suddenly drops after a certain amount of current is reached. The more writes performed on a single word line, the greater the voltage (IR) drop.